The present invention relates to a microwave oven, and more particularly to, an apparatus and a method for detecting abnormal operation of parts of a microwave oven for preventing damage of interior parts of the microwave oven by detecting abnormal functions of parts in trouble.
FIG. 1 is a view showing a structure of heaters and a fan according to a first embodiment of related art microwave oven, and FIG. 2 is a view showing a structure of heaters and a fan according to a second embodiment of related art microwave oven.
First Embodiment
In the related art microwave oven, as shown in FIG. 1, a plurality of heaters 7, 9, 11 disposed between a power supply and a ground are connected with relays 13, 15, 17 for controlling power supply for the respective heaters 7, 8, 9 in serial, that is, the power supply for the heaters 7, 8, 9 is controlled by the on/off operation of the relays 13, 1517.
The heaters 7, 9, 11 are connected with a plurality of cooling fans 19, 21, 23, 25 for preventing overheating due to the heat generated by the heaters when the heaters 7, 9, 11 operate. The cooling fans 19, 21, 23, 25 are also connected to relays 27, 29, 31, 33 in serial so that the operation of the cooling fans 19, 21, 23, 25 is controlled by the relays 27, 29, 31, 33.
Even though unshown, a controller part (unshown) controls the operation of the relays 13, 15, 17 for controlling the power supply for the heaters and the relays 27, 29, 31, 33 for controlling the power supply for the cooling fans. That is, the control part controls the operation of the heaters and the cooling fans according to a current cooking.
In order to prevent damage of parts due to the overheating of the heaters, a thermostat 1 is connected to the heaters. The thermostat 1 is a switch element to be turned on or off above a predetermined temperature.
Therefore, if the thermostat 1 is controlled to be turned off above a predetermined temperature, the power supply for the heaters are shut off in response to the turning off of the thermostat when the temperature is higher than the predetermined temperature by the overheating of the heaters.
Second Embodiment
In the second embodiment, the same reference symbols are utilized for the same components as shown in the first embodiment.
A plurality of heaters 7, 9, 11 are connected between a power supply and a ground in parallel. The respective heaters 7, 9, 11 are connected with relays 13, 15, 17 for controlling power supply for the respective heaters, that is, the power supply for the heaters 7, 8, 9 is controlled by the on/off operation of the relays 13, 1517.
The heaters 7, 9, 11 are connected with a plurality of cooling fans 19, 21, 23, 25 for preventing overheating due to the heat generated by the heaters when the heaters 7, 9, 11 operate. The cooling fans 19, 21, 23, 25 are also connected to relays 27, 29, 31, 33 in serial so that the operation of the cooling fans 19, 21, 23, 25 is controlled by the relays 27, 29, 31, 33.
Even though unshown, a controller part (unshown) controls the operation of the relays 13, 15, 17 for controlling the power supply for the heaters and the relays 27, 29, 31, 33 for controlling the power supply for the cooling fans. That is, the control part controls the operation of the heaters and the cooling fans according to a current cooking.
In order to prevent damage of parts due to the overheating of the heaters, a plurality of thermostats 1, 3, 5 is connected to the heaters. The thermostats 1, 3, 5 are to be a switch element to be turned on or off above a predetermined temperature.
Therefore, if the thermostats are controlled to be turned off above a predetermined temperature, the power supply for the heaters are shut off in response to the turning off of the thermostats when the temperature is higher than the predetermined temperature by the overheating of the heaters.
Now, a process for controlling the operation of the related art heaters and the fans described as above.
The control part (unshown) determines a cooking to be currently processed, and controls operation of the heaters 7, 9, 11 according to power consumption of the cooking. If the currently processing cooking is required to drive the heater 7 only, the control part turns on the relay 13 to supply power to the heater 7.
If the relay 13 is turned on, the heater 7 is supplied with power to generate heat to perform the cooking.
If the current cooking is required to drive all the heaters 7, 9, 11, all the relays 13, 15, 17 are turned on such that the heaters 7, 9, 11 begin to operate in response to the turning on of the relays 13, 15, 17.
On the other hand, if the heater 7 is driven, the controller (unshown) drives the cooling fan 19. While all the heaters 7, 9, 11 are driven, the controller drives all the cooling fans 19, 21, 23.
That is, the cooling fans 19, 21, 23 cool the heat generated by the heaters in association with the operation of the heaters 7, 9, and 11.
The related art apparatus for controlling the heaters and the fans has, however, a disadvantage that it is impossible to detect malfunction of the heaters and the fans. Accordingly, if the heater 7 continues to operate even though the cooling fan 19 is in trouble, environmental parts of the heater 7 are damaged or fire happens due to the overheating of the heater 7.
In order to resolve this disadvantage, thermostats 1, 3, 5 are mounted around the heaters 7, 9, 11 for forcibly shutting off the power supply for the heaters 7, 9, 11 if the generated heat is higher than a predetermined temperature.
However, the construction of the related art apparatus for controlling the heaters and the fans with the thermostats 1, 3, 5 is too complicated and increase the manufacturing cost. And, such a related art apparatus still has disadvantage that it is impossible to detect the malfunction of the heaters or the fans.
Accordingly, it is required to repair the microwave oven due to the re-driving of the microwave oven since the microwave oven is controlled in a worst state by the thermostats 1, 3, 5 when the fans are in trouble, thereby decreasing the reliability of the product.
Accordingly, an object of the present invention is to solve at least the problems and disadvantages of the related art.
Another object of the present invention is to provide an apparatus and a method for detecting abnormal operation of parts of a microwave oven for preventing fire or damage of the parts possibly caused due to the abnormal operation of the parts in trouble in advance.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purposes of the invention, as embodied and broadly described herein, in a microwave oven with a high voltage transformer (HVTxe2x80x2), an apparatus for detecting abnormal operation of parts of the microwave oven comprising: a plurality of heaters connected between a power supply and a ground potential in parallel; a plurality of relays for controlling power supply for the plurality of heaters; cooling fans to be driven in response to the operation of the heaters for cooling heat generated by the heaters; a current transformer for detecting currents used by the eaters, the cooling fan, and the high pressure transformer; and a control part for monitoring operational states of the heaters, the cooling fan and the high pressure transformer according to comparison result of a preset current amount with the current amount detected by the current transformer.
To achieve the objects and in accordance with the purposes of the invention, as embodied and broadly described herein, a method of detecting abnormal operation state of parts of a microwave oven including a memory, a plurality of heaters and a cooling fan, comprising the steps of: extracting cooking data selected by a user from the memory; driving the cooling fan according to the extracted cooking data; determining whether or not to drive the heaters according to whether a driving current of the cooling fan is higher than a first preset current or not and detecting an abnormal state of the cooling fan; and determining whether or not to advance the cooking according to whether a driving current of the heaters is higher than a second present current as the heaters are driven, and detecting an abnormal state of the heaters.
According to the present invention, the cooling fans and the heaters operate individually and abnormal operation of the cooling fans and the heaters are determined by comparison of current values detected during the operation with reference current values.
According to the present invention, the cooling fans and the heaters operate from one having a lower load in sequence and a reference current value of a load to be compared later is set by adding a current value compared previously.
According to the present invention, when a plurality of the cooling fans and the heaters operate simultaneously, the reference current value is set corresponding to the number of the operating plurality of cooling fan and the heaters.